Mercedes-Benz shows sketch of topless S-Class

The big, full-size convertible used to be a staple of the big American life. Well, now it's back -- and its German.

Mercedes-Benz released a sketch Saturday night of what it is calling its S-Class Cabriolet. It's a giant droptop in the tradition of the old Lincolns or Cadillacs of the 1960s -- only fully updated for the times. Mercedes is offering scant details, saying only that it will become the sixth iteration of the S Class, its flagship model, and its first four-seat convertible since 1971.

Cadillac was the last one to hint at full-size convertible with its Ciel concept, which made its debut in Carmel, Calif., as part of Monterey Car Week in 2011. The full-size Cadillac made its debut this year as the CT6, but so far no convertible version has been announced.

With gas prices low, the timing could be right. But Mercedes gave no indication as to its timing for the new model.